Geremi and Didier Drogba scored as Chelsea maintained their 100% start to the season, while Sunderland are still looking for their first point.
Frank Lampard struck the woodwork with a thunderous drive before a mistake from Andy Welsh led to Geremi's goal.
Welsh lost control after a throw from Kevin Davis and Geremi struck a low shot the keeper should have saved.
Davis then saved from Arjen Robben and Joe Cole but was powerless to stop Drogba's far-post header late on.
Chelsea were far from their fluent best - too often needlessly squandering possession - and rarely threatened before their 54th-minute opener.
But they have now won their opening five games without conceding and appear to be constructing a strong defence of their Premiership title.
Luckless Sunderland are still searching for their first point this season and remain bottom of the table.
The Black Cats have not picked up a Premiership point since a draw with Blackburn in January 2003 during their relegation campaign - a run that now extends to 20 games.
Sunderland nearly got off to an awful start when Davis was almost embarrassed by an early strike from Asier del Horno that swerved through the air.
The Sunderland keeper was caught slightly out of position but managed to make a one-handed save.
But Chelsea, with Hernan Crespo preferred to Drogba up front, struggled to open up their lowly placed visitors in the opening half.
And an optimistic long-range strike from Lampard that flew well wide shortly before half-time testified to their mounting frustration.
Sunderland, with Justin Hoyte and Christian Bassila on debut, stifled their opponents while looking to push forward as often as possible.
Jonathan Stead made one surging run into the Chelsea area but could not pick out a team-mate.
Jose Mourinho introduced Damien Duff at half-time and he was quickly followed by Drogba and Cole.
Lampard's strike hit the crossbar just after the break, before a series of individual errors led to Geremi's goal.
Substitute Welsh lost possession of a throw out from Davis and Geremi drilled a low long-range strike that flew under the body of Sunderland's despairing keeper.
Davis denied Robben and Cole as Chelsea searched for a decisive second goal.
And it finally came when Drogba converted Duff's cross from the left.
Del Horno limped off inside the last 10 minutes, leaving Chelsea - who had used all their substitutes - to complete the game with 10 men.
Chelsea manager Jose Mourinho:
"The players lose condition and form so these games (after international breaks) are always difficult.
"I'm very happy to have won the game. The result was great for us but the performance was not so good.
"Asier del Horno, for example, has been training two times a day, while some do not train much."
Sunderland boss Mick McCarthy:
"We have got to keep playing and believing and hope we win that all-important game.
"Effort and application are fine but sometimes we lack a bit of belief.
"We have West Brom at home now and that is vital for us. I would still rather be here in the Premiership than at Championship clubs like last season."
Chelsea: Cech, Geremi, Gallas, Terry, Del Horno, Essien, Wright-Phillips (Joe Cole 57), Lampard, Gudjohnsen (Duff 45), Robben, Crespo (Drogba 54).
Subs Not Used: Ricardo Carvalho, Cudicini.
Booked: Joe Cole.
Goals: Geremi 54, Drogba 82.
Sunderland: Davis, Nosworthy, Breen, Stubbs (Welsh 52), Hoyte, Bassila, Elliott, Whitehead, Miller (Le Tallec 80), Arca, Stead (Gray 45).
Subs Not Used: Robinson, Alnwick.
Ref: M Dean (Wirral).